The invention relates to the relatively-rotatable combination of a shaft and a sealing ring thereabout.
A known seal for sealing about a rotatable shaft has a stationary annular polymeric sealing ring. An inner, sealing surface of the ring resiliently flares against a counter surface on the shaft to form a seal therebetween. To aid this, the sealing surface has at least one hydrodynamically-acting back-feed element for pumping back fluid which seeps between the sealing and counter surfaces upon the rotation therebetween.
U.S. Pat. No. 3,572,732 describes a shaft seal of this type. It has excellent reliability of operation as long as the seal is in like-new condition. Deposits from the sealed fluid, for example entrained particles as are especially likely from lubricating oil, can quickly change this condition, however. Premature failure of the seal is the consequence.